The incidence of cancer in both humans and animals is increasing. Due to an ever increasing life expectancy and environmental factors, the incidence of cancer-related medical claims is increasing year after year. Among the known cancer-causing/contributing factors are microbial infections (e.g., virii), chemicals and radiation exposure and genetic inheritance. These factors can cause numerous types of cancers, the virulence of which depends on the affected tissue/organ, the location in the body and the reaction of the body to the cancer.
Treatment for cancer is improving with an ever growing range of available drugs and radiation treatments even though the diagnosis of the cancer type and location and subsequently the treatment and the monitoring have to be carefully devised on a patient-by-patient basis, given the large number of different types of cancer. However, one common aspect that significantly improves the success rate of treatment is early detection. For most cancer types early detection improves the outcome of the treatment and the management of the disease.
Since early detection of cancer plays such a crucial role in the success of the treatment (e.g., survival rate of patients), the screening of some cancers (e.g., breast cancer, colon cancer) may be recommended even in subjects appearing healthy and without showing symptoms that may be attributed to cancer. However, screening is typically a medical (or veterinary) procedure that may be invasive (e.g., requires biopsies) and is generally too expensive to make it a routine procedure in non-suspected patients. Additionally, because of the cost a practitioner may be reluctant to order a full screening for cancer when a patient is showing only mild symptoms or a few symptoms that would indicate cancer.
Therefore, there is a need for screening methods for cancer that are cost effective, and least invasive allowing a practitioner to detect cancer at an early stage and pursue other methods of diagnosis and treatment. The same methods may be used to monitor subjects during and after treatment cost-effectively.